It is known to remove cells, e.g., lymphocytes, from a patient's blood, grow them in culture medium, harvest the cultured cells, and separate the cells from the culture medium and metabolites before returning the cells to a patient, e.g., Muul, Linda, M., et al., "Large scale production of human lymphokine-activated killer cells for use in adoptive immunotherapy", Journal of Immunoloqical Methods, Vol. 88 (1986), pp. 265-275; Muul, Linda, M., et al., "Development of an automated closed system for generation of human lymphokine-activated killer (LAK) cells for use in adoptive immunotheraphy", Journal of Immunolooical Methods, Vol. 101 (1987), pp. 171-181. A Cobe Laboratories, Inc. (IBM) 2991 centrifuge has been used in such procedures to separate cells from the culture medium and metabolites prior to returning the cells to a patient. The cells are subjected to plural centrifuge operations with application of a rinse solution between centrifuge operations after the cells have been concentrated. The use of the 2991 centrifuge to concentrate and wash other types of cells is described in Gilmore, M.J.M.L., et al., "A Technique for the Concentration of Nucleated Bone Marrow Cells for in vitro Manipulation or Cryopreservation Using the IBM 2991 Blood Cell Processor", Vol. 45, Vox Sano. (1983), pp. 294-302; Wooten, M.J. et al., "Use and Analysis of Saline Washed Red Blood Cells", Vol. 16, No. 5, Transfusion (1976) pp. 464-468.